Mairi,

"Treat the cause of problem, in this case, weak quads, hams, glut med etc strengthen the knee, propriception, correct posture and you won't get secondary Lx problems and Lx neuro"
since when do weaknesses in quads, hams or gluteals cause either knee pain or OA?
what has proprioceptive loss got to do with the cause of pain ?( or OA for that matter )
please explain what posture has to do with these issues in terms of aetiological relationship, and the reverse, it's potential , when addressed, to affect either pain or OA?
Let's be clear, I'm not saying these elements ought not be a part of physio interventions where knee pain is present , just interested in how you have been able to confidently claim a causal relationship.
In fact there is no reason to think weakness , per se, is involved in a pain or OA causing mechanism at all. Do all those who are weak in the legs get OA or knee pain?, some ? a few ? . Inferring cause is difficult under even RCT conditions . experiencing a relationship is another matter entirely.
Were you , or anyone skilled in continuous Wikipedia reference-linkfacet joint mobilisation techniques ( particularly CM ), to approach a person with retropatella knee pain and find hypomobility at L3, and then mobilise that joint , untill protective paravertebral tone was normalised around that joint, you would find within ten to fifteen minutes of beginning CM , that the complained of retropatella pain , along with altered VMO recruitment would be returned to a normal pain free state, or approaching same.
similarly where LE/tenniss elbow is felt , a similar result would be evident after mobs to C456. In this way it is possible to assert a RELATIONSHIP, between facet joint behaviour and responses and complained of pain. Thus alerting the skilled therapist to the prospect , that continued efforts with the same focus , may reveal further improvements to the features of LE. This scenario , is what I allude to and one I see repeated over and over in MSK conditions . Better still , This method is not a temporary means to relieve pain, but in fact the best means to entirely eliminate LE ( and FYI PFS ). generally one to three treatments, with some attention needed to biomechanical concerns which gave rise to the spinal dysfunction .